Think about all your own uses of IP in your house or office? Are you really messing with anything but four part IPV4 addressing? In fact I'd go as far as to say that almost everything you do/configure is probably somewhere under 192.168.x.x

Sure you may set up some DNS servers (probably 8.8.8.8 and 8.8.4.4 in fact!) with a more global IP range but even then it's still IPv4 not v6.

Maybe the Cisco's of this world and the others that provide the "backbone" of the internet concern themselves with IPv6 - but domestic use? Even more so, "embedded micro" domestic use ? I don't think so.

I don't see the point in being able to directly address every single lightbulb in my from anywhere in the world.

More to the point, I see a need to >>prevent<< direct access to every single light bulb from anywhere in the world. Do you trust the light bulb manufacturer to get security right? Or do you do the sensible thing and put it behind a routing/NATting firewall? Will you have a trillion light bulbs behind that firewall?

"Experience is what enables you to recognise a mistake the second time you make it."

Designed to provide developers with a concrete roadmap to IoT security, the ARM PSA [Platform Security Architecture] combines a security use-case analysis with hardware/firmware specifications and an open-source reference implementation ...

...

FreedomBox combines firewall and some local device access with (planned) mesh networking :